i was messing with a friend's jailbroken iPhone, i needed it in dfu mode to restore it but i probably did something wrong because phone is stuck with a blank screen and nothing can make iTunes recognize it.

it's an unlocked iPhone 4 running a jb 5.0.0 iOS.

i really can't get it to boot no matter what.
it doesn't even show under usb devices currently connected.

i left it connected to the wall charger -i read somewhere that while in dfu mode, phone isn't really charged, but someone said it helped somehow- without any success.

i'd prefer not to have apple service it because i guess they can boot it and see it has been jb.

Easiest way is holding power and home togeteher, count to 10 and release power, while holding home for another 7 seconds, sometimes the phone gets into a semi-off/DFU state. Looks like its completely dead, leave plugged in USB for 10 min before doing the above.

i7:~ m_admin$ /Users/m_admin/Desktop/fixrecovery-osx/fixrecovery43 ; exit;
Initializing libpois0n
No matching processes belonging to you were found
Waiting for device to enter DFU mode
Device must be in DFU mode to continue
[..]

1. Power off.
2. Hold down home button.
3. With home button held down plug in cable, connected to computer, iTunes open.
4. Continue holding home button until connect to iTunes appears on screen of phone.

1. Power off.
2. Hold down home button.
3. With home button held down plug in cable, connected to computer, iTunes open.
4. Continue holding home button until connect to iTunes appears on screen of phone.

hello im new here but i could do with some help a while back my iphone 4 decided to randomly turn itself off while on charge after this it just showed a blank screen will not turn on ive tried redsnow tried the reset with the home and power button tried doing that backwards leaving it on charge the only thing it does do is go into dfu mode ive also taken the battery out and put it back in nothing but the other day it did show a pic of a battery with low battery then i tried to reset it and its stuck again in dfu mode or whatever it is blank screen if anyone could help that would be great.

1 month ago I put my 5s to charge at 50%. Left it alone for 30mins TOPS.

I came back. Black screen. Nothing worked. Nothing helped. iTunes could see it but it was in DFU. But nothing. Nothing would kick it out. Any button combo just rebooted it back to DFU with the screen black

If I restored it, the process would start, I'd get an apple logo with a progress line. Then error 40 would stop it. Tried it on 2 windows and 1 Mac with 4 USB cables. Apple said this a known issue on any phone from 4-5s regardless of iOS. That it's a HW malfunction ... Usually I'm the USB port

Even letting the phone drain out of power and turning off did not work. Plugged it in and nothing. 5 mins later, iTunes saw it in DFU. Still black screen